Liquid chromatography system, method and use

ABSTRACT

A method performed in a liquid chromatography system includes a metering device pushing a sample into a trap column. The metering device sucks in the sample from a sample reservoir, wherein the sucking in the sample from a sample reservoir precedes the step of pushing the sample into the trap column. The liquid chromatography system also includes a trap column and a metering device, wherein the system is adapted to assume a configuration allowing the metering device to push a sample into the trap column and wherein the metering device is adapted to push the sample into the trap column in this configuration, wherein the system is adapted to assume a configuration allowing the sample to be sucked into the system by means of the metering device. Furthermore, the invention relates to a use of the liquid chromatography system for liquid chromatography, in particular of high-pressure liquid chromatography.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation under 35 U.S.C. §120 and claims thepriority benefit of co-pending U.S. patent application Ser. No.15/809,136, filed on Nov. 10, 2017, which claims the priority benefitunder 35 U.S.C. §119 to German Patent Application No. DE 10 2016 121512.0, filed on Nov. 10, 2016, the disclosure of each of the foregoingapplications is incorporated herein by reference.

FIELD OF THE INVENTION

The invention lies in the field of liquid chromatography (LC) andparticularly in the field of High Performance Liquid Chromatography(HPLC). The goal of this analytical method is the division of a sampleinto its constituent parts followed by quantifying of their respectiveproportions, or a simple separation. More particularly, the presentinvention relates to a liquid chromatography system, a method performedin such a system and a corresponding use of such a system.

BACKGROUND

In LC systems, a liquid sample is introduced with an analytical pumpinto a separation column. Different constituents of the sample adhere tothe separation column in a different manner. A pump pushes a solvent (ordifferent solvents) through the separation column. Depending on, interalia, the adherence of the constituents to the separation column, thesolvent, the flow rate of the solvent and the pressure of the solvent,the different constituents of the sample need different amounts of timeto pass through the separation column; generally, the more strongly aconstituent interacts with the separation column, the longer it willneed to pass through the separation column. This allows the constituents(and thus, the sample) to be determined and analyzed.

Introducing the sample into the separation column typically comprisesdifferent steps including (1) a sample pick up means, such as a needle,being introduced into a sample reservoir and picking up the sample. (2)The sample may then be introduced from the needle into a section forintermediate storing of the sample. Subsequently, (3) the sample may beintroduced from the section for intermediate storing of the sample intothe separation column. For this purpose, injection valves may be used.Such injection valves or distribution valves may connect different portswith one another to establish a fluid connection between different partsor sections of an LC system. For example, U.S. Pat. No. 3,530,721discloses an apparatus for supplying liquid samples into a separationcolumn. The apparatus includes a switch that can be switched from onestate allowing a sample to be drawn into a receptacle (e.g., forcarrying our steps (1) and (2)) to another state allowing the sample tobe pumped from the receptacle into a column (e.g., for carrying out theabove described step (3)). U.S. Pat. No. 4,939,943 discloses an injectorincluding a high pressure syringe unit and a valve unit for LC, whichvalve unit is adapted to assume different positions, one for sample pickup and one for introducing the sample into a chromatographic column.

A further variant of LC systems includes a so-called trap column.Instead of intermediate storing of the sample in a simple section oftubing or in a simple receptacle, the sample may first be introducedinto a trap column and constituents of the sample may adhere to the trapcolumn (which may also be called a “pre-column”). Thus, by means of thetrap column, the sample may be concentrated. In other words, wheninjecting the sample through a trap column, the sample is guided withthe help of a pumping device through the trap column (or pre-column).The sample components remain hanging in the column on the material inthe column. The sample can therefore be concentrated. Subsequently, thesample may be entrained in an analytical flow from the trap columnthrough the separation column. Again, switching from the first step(introducing a sample into the trap column) to the second step(providing a flow to introduce the sample from the trap column to theseparation column) may be done by switching of a valve. In other words,after introducing the sample into the trap column, the trap column isconnected with an analytical flow, the sample detaches from the trapcolumn, and is guided into the separation column (which may also bereferred to as an analytical column). The separation of the sample fromthe trap column is enabled by the interaction of the sample with thecolumn and the flow.

A part of such systems are samplers that are responsible for samplemanagement and accurate collection of the sample. After samplecollection, the sample is either brought to an analytical fluid path bythe switching of valves, or first pumped into the above described trapcolumn for concentration with the help of a pumping device. The trapcolumn is then connected to the analytical fluid path, as also describedabove.

The analytical pump then either pushes the sample directly through thetrap column (continuation of the flow direction) or away from the trapcolumn to the separation column (reversal of the flow direction). In theseparation column, the sample separation then takes place due to thedifferent interactions of the sample constituents with the column andthe flow. After the column, the sample is passed through a detector thatdetects each constituent of the sample, e.g. by optical detection.

That is, in very simple words, a sample is picked up and introduced intoa trap column. The trap column is then fluidly connected to a separationcolumn and the sample is supplied from the trap column to the separationcolumn. The supplying of the sample from the trap column to theseparation column is typically done by means of an analytical pumpproviding a pressure exceeding the atmospheric pressure. In HPLC, thispressure may be on the order of 1000 bar, such as 1500 bar.

For the above described process, LC systems are typically used. Suchsystems typically comprise a plurality of components, including a samplepick up means, a metering device for introducing a desired amount of asample into the system, a separation column for separating theconstituents of the sample and pumps for providing a flow between thecomponents. As discussed, a trap column may also be provided, e.g., forsample concentration. The discussed components may be fluidly connectedwith each other (i.e., connected in such a way that fluid may flow fromone component to another and/or vice versa) by means of a valve, whichvalve may also be referred to as a switching valve or a distributionvalve. Such a valve may selectively connect the components to oneanother.

While known systems are satisfactory in some regards, they have certaindisadvantages and limitations. For example, as discussed, the knownsystems comprise a plurality of different components. This make thesesystems complex and prone to failure, as each component may malfunction.The complexity of the systems also makes such systems difficult toservice. Furthermore, such complex systems also need a relatively largeamount of space.

SUMMARY

In light of the above, it is an object of the present invention toovercome or at least alleviate the shortcomings and disadvantages of theprior art. In particular, it is an object of the present invention toprovide a system and a corresponding method decreasing the complexity ofthe systems, being more failsafe, being less prone to failure, taking upless space and/or being simpler to service.

These objects are met by the present invention.

In one embodiment, these objects are met by a method in accordance withthe present invention. The method is performed in a liquidchromatography system and the method comprises a metering device pushinga sample into a trap column.

In other words, the metering device causes a positive pressure whichcauses the sample to be transferred (from another component) to the trapcolumn.

This may be different to some prior art technologies. In the prior art,when a trap column was used, there was usually provided an additionalpump for bringing the sample into the trap column (i.e., onto thematerial of the trap column). In contrast, the present invention usesthe metering device to bring the sample into the trap column. That is,the invention relates a method for loading the sample into the trapcolumn without a separate pumping device. In still other words, themetering device is used for additional tasks. This renders theadditional pump used in the prior art to bring the sample into the trapcolumn superfluous. Thus, a system with less parts may be provided,resulting in a simpler and less complex system. Such a system may alsobe less prone to failure and simpler to service (as there are fewerparts).

It will be understood that the sample may be a liquid sample. As willfurther be understood, when the sample is introduced into the trapcolumn, some constituents of the sample will adhere to the trap columnwhile other constituents may not adhere and may flow through the trapcolumn and go to waste (which may also be referred to as a wastereservoir). That is, the sample being introduced and adhering to thetrap column does not necessarily have exactly the same composition asthe original sample. The same applies to the sample which is suppliedfrom the trap column to a separation column. E.g., depending on the typeof solvent used, only some constituents of the sample adhering to thetrap column may be introduced to the separation column. For sake ofbrevity and simplicity of description, however, all of the above willsimply be referred to as “the sample”—although it is clear to theskilled person that the sample originally introduced into a systemcarrying out the described method does not necessarily correspond to100% to the sample that is supplied to the separation column andsubsequently analyzed.

The method may further comprise the metering device sucking in thesample from a sample reservoir, wherein sucking in the sample from asample reservoir precedes the step of pushing the sample into the trapcolumn. That is, in other words, the method comprises the sample beingsucked up by means of the metering device and then being brought intothe trap column by means of the metering device. It should be noted thatthe step of the sample being brought into the trap column may beperformed directly after the sample is sucked in. However, in someembodiments, there may also be one or more additional steps betweensucking in the sample and bringing the sample into the trap column.

The liquid chromatography system may further comprise a separationcolumn and the method may further comprise fluidly connecting the trapcolumn to the separation column and pushing the sample from the trapcolumn to the separation column.

The sample may be pushed into the trap column in a first flow directionand the sample may be pushed from the trap column to the separationcolumn in a second flow direction, which second flow direction isopposite to the first flow direction. That is, the sample may be broughtinto the separation column in a direction opposite to the direction inwhich the sample was introduced into the trap column. This configurationmay also be referred as “backward flush”. In some instances, such abackward flush may be advantageous, as the sample introduced into theseparation column does not have to travel through the complete trapcolumn.

The sample may be pushed into the trap column in a first flow directionand the sample may be pushed from the trap column to the separationcolumn in a second flow direction, which second flow direction is in thesame direction as the first flow direction. This state may also bereferred to as “forward flush”. That is, any constituents of the sampleintroduced into the separation column has passed through the completelength of the trap column. This may lead to a purer sample, which may beadvantageous in some instances.

The method may further comprise pressurizing the trap column to a firstpressure, while the trap column is isolated from ambient atmosphere,wherein the step of pressurizing the trap column to the first pressureis performed before the trap column is fluidly connected to theseparation column. That is, the trap column may be pre-pressurized,e.g., to the analytical pressure. This may prevent (or decrease) theoccurrence of sudden pressure spikes at the trap column fluidlyconnected to the trap column, thereby decreasing sample dispersion andwear on these systems. Thus, the system's service life may be increased.

The liquid chromatography system may comprise an analytical pump andwherein the method further comprises fluidly connecting the trap columnto the analytical pump and wherein the analytical pump pushes the samplefrom the trap column to the separation column.

The step of pressurizing the trap column to the first pressure may beperformed before the trap column is fluidly connected to the analyticalpump.

The first pressure may exceed the ambient pressure by at least 10 bar,preferably at least 100 bar, more preferably at least 500 bar.

The metering device may pressurize the trap column. That is, themetering device causes a positive pressure in the trap column. In otherwords, the metering device is not only used to introduce the sample intothe trap column, but also to pressurize the trap column. Again, in priorart devices, an additional pump may have been used for this purpose andagain, by integrating this additional functionality into the meteringdevice, there are less parts used, thereby rendering the system lesscomplex.

The liquid chromatography system may further comprise a waste and themethod may further comprise fluidly connecting the trap column to thewaste and causing a fluid flow from the trap column to the waste.

The metering device may cause the fluid flow from the trap column to thewaste. Once more, having this functionality also in the metering devicemay decrease the complexity of the system used.

The method may further comprise depressurizing the trap column from anelevated pressure to a reduced pressure before the trap column isfluidly connected to the waste. Such a controlled decompression may beadvantageous, as it leads to less abrasion than could occur if no suchcontrolled decompression was performed. Furthermore, the controlleddecompression also prevent fluids from rapidly exiting the system(potentially being harmful to a user) and lowers the risk ofconstituents outgassing in the fluid in the system.

The elevated pressure may exceed the reduced pressure by at least 10bar, preferably at least 100 bar, more preferably at least 500 bar.

The metering device may depressurize the trap column from the elevatedpressure to the reduced pressure. Again, having this additionalfunctionality performed by the metering device may result in a lesscomplex and more fail-safe system.

The metering device may comprise a first port and a second port and themethod may comprise fluidly connecting the metering device by means ofthe first port with a first solvent reservoir and the metering devicesucking in solvent from the first solvent reservoir.

The step of the metering device sucking in solvent from the firstsolvent reservoir may be performed after the metering device pushes thesample into the trap column.

The step of the metering device sucking in solvent from the firstsolvent reservoir may also performed before the metering device pushesthe sample into the trap column. That is, in this embodiment, solvent issucked into the metering device both before and after the sample ispushed to the trap column. That is, these steps may be performediteratively: First, solvent may be sucked into the metering device.Then, the sample may be introduced into the trap column. Then, moresolvent may be introduced into the trap column.

The metering device may be fluidly connected to a sample pick up meansby means of the second port and the method may comprise the sample pickup means being moved to the solvent reservoir and the first port may befluidly connected to a dead end when the sample is sucked in.

Put differently, the first port is not fluidly connected to a solventreservoir when the sample is sucked in.

The liquid chromatography system may comprise a sample pick up meansseat, a first distributor valve and a second distributor valve, whereineach distributor valve comprises a plurality of ports and a plurality ofconnecting elements for changeably connecting the ports of therespective distributor valve, wherein as regards the first distributorvalve, one port is directly fluidly connected to the seat, two ports aredirectly fluidly connected to the trap column, one port is directlyfluidly connected to the separation column, one port is directly fluidlyconnected to the analytical pump and one port is directly fluidlyconnected to the second distributor valve; and as regards the seconddistributor valve, one port is directly fluidly connected to the firstdistributor valve, one port is directly fluidly connected to the waste,one port is directly fluidly connected to a first solvent reservoir andone port is directly fluidly connected to the metering device.

In this document, a fluid connection (or two elements being fluidlyconnected to one another) means that fluid may flow from one element toanother. A port of a valve being directly fluidly connected to anotherelement should be construed to mean that the port is fluidly connectedto the other element in such a manner that there is no other valve portinterposed between the port of the valve and the other element.

Another port of the second distributor valve may be directly fluidlyconnected to a second solvent reservoir.

The sample pick up means may be a needle.

The metering device may comprise a housing and a piston.

In a further embodiment, the present invention relates to a system foruse in liquid chromatography. The system comprises a trap column and ametering device. The system is adapted to assume a configurationallowing the metering device to push a sample into the trap column andthe metering device is adapted to push the sample into the trap columnin this configuration.

That is, the system is adapted to perform the method of the invention.Thus, a system is provided requiring less parts for its functionality,leading to a less complex, more reliable, more failsafe and smallersystem.

The system may be adapted to assume a configuration allowing the sampleto be sucked into the system by means of the metering device.

The system may further comprise a sample pick up means fluidly connectedto the metering device. The sample pick up means may be a needle.

The system further may comprise a seat for receiving the sample pick upmeans.

The system may further comprise a separation column and an analyticalpump adapted to push the sample towards and through the separationcolumn.

The system may further comprise a waste.

The system may further comprise a first solvent reservoir.

The system may further comprise a second solvent reservoir.

The system may further comprise a first distributor valve and a seconddistributor valve, wherein each distributor valve comprises a pluralityof ports and a plurality of connecting elements for changeablyconnecting the ports of the respective distributor valve, wherein asregards the first distributor valve, one port is directly fluidlyconnected to the seat, two ports are directly fluidly connected to thetrap column, one port is directly fluidly connected to the separationcolumn, one port is directly fluidly connected to the analytical pumpand one port is directly fluidly connected to the second distributorvalve; and as regards the second distributor valve, one port is directlyfluidly connected to the first distributor valve, one port is directlyfluidly connected to the waste, one port is directly fluidly connectedto a first solvent reservoir and one port is directly fluidly connectedto the metering device.

Another port of the second distributor valve may be directly fluidlyconnected to the second solvent reservoir.

The system may be adapted for high pressure liquid chromatography, andpreferably for pressures exceeding 1000 bar.

The metering device may comprise a first port and a second port tofluidly connect to other components.

The metering device may be fluidly connected to the first distributorvalve by means of the second port and fluidly connected to the seconddistributor valve by means of the first port.

The system may not comprise any pump other than the metering device tointroduce the sample into the trap column.

The system may be adapted to carry out the method recited herein.

The present invention also relates to a use of the system discussedabove for liquid chromatography and in particular for high pressureliquid chromatography.

Also this use provides the usage of an improved system and/or animproved method in liquid chromatography. That is, liquid chromatographymay be carried out in a more fail-safe, more economic manner by usingless space than compared to what was required before.

In particular, the present invention also relates to a use of the systemto carry out the method as recited herein.

The metering device may be used to push the sample into the trap column.

The metering device may be used to suck in the sample.

The metering device may be used to pressurize the trap column before thetrap column is fluidly connected to the separation column.

The metering device may be used to depressurize the trap column from anelevated pressure to a reduced pressure.

The metering device may be used to cause a fluid flow from the trapcolumn to a waste.

The metering device may be used to suck in solvent.

That is, the described invention uses the metering device in multipleways: First, it is responsible for the precise sample collection, thenit conveys the sample into the trap column. The metering device is thusused as both a sample collector and a pump. In some embodiments, themetering device may have a volume too limited to achieve the sampleloading in one step. In such embodiments, the loading flow may beinterrupted, the metering device is filled again, and only then theloading is continued. As discussed, after loading, the metering devicemay pre-compress the sample, and, after injection, the metering devicemay wash (purge). In one position (which may be referred to as thebypass position), for example during the equilibrium phase, the meteringdevice may also rinse the trap column.

That is, to summarize, the metering device may have the following fourfunctions: sample measuring, pre-compressing the trap column, providingthe loading flow (if needed, with different solvents) and washing (ifneeded, with different solvents). The integration of further functionsin the metering device saves costs and space. The reduction of thenumber of components facilitates maintenance and reduces the complexityof the system.

The invention is also defined by the following numbered embodiments:

Below, method embodiments will be discussed. These embodiments areabbreviated by the letter “M” followed by a number. When reference isherein made to a method embodiment, those embodiments are meant.

M1. A method performed in a liquid chromatography system, the methodcomprising a metering device pushing a sample into a trap column.

In other words, the metering device causes a positive pressure whichcauses the sample to be transferred (from another component) to the trapcolumn.

It will be understood that the sample may be a liquid sample. As willfurther be understood, when the sample is introduced into the trapcolumn, some constituents of the sample will adhere to the trap columnwhile other constituents may not adhere and may flow through the trapcolumn and go to waste (which may also be referred to as a wastereservoir). That is, the sample being introduced and adhering to thetrap column does not necessarily have exactly the same composition asthe original sample. The same applies to the sample which is suppliedfrom the trap column to a separation column. E.g., depending on the typeof solvent used, only some constituents of the sample adhering to thetrap column may be introduced to the separation column. For sake ofbrevity and simplicity of description, however, all of the above willsimply be referred to as “the sample”—although it is clear to theskilled person that the sample originally introduced into a systemcarrying out the described method does not necessarily correspond to100% to the sample that is supplied to the separation column andsubsequently analyzed.

M2. The method in accordance with the preceding embodiment, wherein themethod further comprises the metering device sucking in the sample froma sample reservoir, wherein sucking in the sample from a samplereservoir precedes the step of pushing the sample into the trap column.

M3. The method in accordance with any of the preceding embodiments,wherein the liquid chromatography system comprises a separation columnand wherein the method further comprises fluidly connecting the trapcolumn to the separation column and pushing the sample from the trapcolumn to the separation column.

M4. The method in accordance with any of the preceding embodiments,wherein the sample is pushed into the trap column in a first flowdirection and wherein the sample is pushed from the trap column to theseparation column in a second flow direction, which second flowdirection is opposite to the first flow direction.

M5. The method in accordance with embodiment M3, wherein the sample ispushed into the trap column in a first flow direction and wherein thesample is pushed from the trap column to the separation column in asecond flow direction, which second flow direction is in the samedirection as the first flow direction.

M6. The method in accordance with any of the preceding embodiments withthe features of embodiment M3, wherein the method further comprisespressurizing the trap column to a first pressure, while the trap columnis isolated from ambient atmosphere, wherein the step of pressurizingthe trap column to the first pressure is performed before the trapcolumn is fluidly connected to the separation column.

M7. The method in accordance with any of the preceding embodiments withthe features of embodiment M3, wherein the liquid chromatography systemcomprises an analytical pump and wherein the method further comprisesfluidly connecting the trap column to the analytical pump and whereinthe analytical pump pushes the sample from the trap column to theseparation column.

M8. The method with the features of the two preceding embodiments,wherein the step of pressurizing the trap column to the first pressureis performed before the trap column is fluidly connected to theanalytical pump.

M9. The method in accordance with any of the preceding embodiments withthe features of embodiment M6, wherein the first pressure exceedsambient pressure by at least 10 bar, preferably at least 100 bar, morepreferably at least 500 bar.

M10. The method in accordance with any of the preceding embodiments withthe features of embodiment M6, wherein the metering device pressurizesthe trap column.

That is, the metering device causes a positive pressure in the trapcolumn.

M11. The method in accordance with any of the preceding embodiments,wherein the liquid chromatography system further comprises a waste andwherein the method further comprises fluidly connecting the trap columnto the waste and causing a fluid flow from the trap column to the waste.

M12. The method in accordance with the preceding embodiment, wherein themetering device causes the fluid flow from the trap column to the waste.

M13. The method in accordance with any of the two preceding embodiments,wherein the method further comprises depressurizing the trap column froman elevated pressure to a reduced pressure before the trap column isfluidly connected to the waste.

M14. The method in accordance with the preceding embodiment, wherein theelevated pressure exceeds the reduced pressure by at least 10 bar,preferably at least 100 bar, more preferably at least 500 bar.

M15. The method in accordance with any of the two preceding embodiments,wherein the metering device depressurizes the trap column from theelevated pressure to the reduced pressure.

M16. The method in accordance with any of the preceding embodiments,wherein the metering device comprises a first port and a second port andwherein the method comprises fluidly connecting the metering device bymeans of the first port with a first solvent reservoir and the meteringdevice sucking in solvent from the first solvent reservoir.

M17. The method in accordance with the preceding embodiment, wherein thestep of the metering device sucking in solvent from the first solventreservoir is performed after the metering device pushes the sample intothe trap column.

M18. The method in accordance with the preceding embodiment, wherein thestep of the metering device sucking in solvent from the first solventreservoir is also performed before the metering device pushes the sampleinto the trap column.

That is, in this embodiment, solvent is sucked into the metering deviceboth before and after the sample is pushed to the trap column.

M19. The method in accordance with any of the preceding 3 embodimentsand with the features of embodiment M2, wherein the metering device isfluidly connected to a sample pick up means by means of the second portand wherein the method comprises the sample pick up means being moved tothe solvent reservoir and wherein the first port is fluidly connected toa dead end when the sample is sucked in.

Put differently, the first port is not fluidly connected to a solventreservoir when the sample is sucked in.

M20. The method in accordance with any of the preceding embodiments withthe features of embodiments M3, M7, M11, M16, wherein the liquidchromatography system comprises a sample pick up means seat, a firstdistributor valve and a second distributor valve, wherein eachdistributor valve comprises a plurality of ports and a plurality ofconnecting elements for changeably connecting the ports of therespective distributor valve, wherein as regards the first distributorvalve, one port is directly fluidly connected to the seat, two ports aredirectly fluidly connected to the trap column, one port is directlyfluidly connected to the separation column, one port is directly fluidlyconnected to the analytical pump and one port is directly fluidlyconnected to the second distributor valve; and as regards the seconddistributor valve, one port is directly fluidly connected to the firstdistributor valve, one port is directly fluidly connected to the waste,one port is directly fluidly connected to a first solvent reservoir andone port is directly fluidly connected to the metering device.

In this document, a fluid connection (or two elements being fluidlyconnected to one another) means that fluid may flow from one element toanother. A port of a valve being directly fluidly connected to anotherelement should be construed to mean that the port is fluidly connectedto the other element in such a manner that there is no other valve portinterposed between the port of the valve and the other element.

M21. A method in accordance with the preceding embodiment, whereinanother port of the second distributor valve is directly fluidlyconnected to a second solvent reservoir.

M22. A method in accordance with any of the preceding embodiments withthe features of embodiment M19, wherein the sample pick up means is aneedle.

M23. A method in accordance with any of the preceding embodiments,wherein the metering device comprises a housing and a piston.

Below, system embodiments will be discussed. These embodiments areabbreviated by the letter “S” followed by a number. When reference isherein made to a system embodiment, those embodiments are meant.

S1. A liquid chromatography system comprising a trap column and ametering device, wherein the system is adapted to assume a configurationallowing the metering device to push a sample into the trap column andwherein the metering device is adapted to push the sample into the trapcolumn in this configuration.

S2. The liquid chromatography system in accordance with the precedingembodiment, wherein the system is adapted to assume a configurationallowing the sample to be sucked into the system by means of themetering device.

S3. The liquid chromatography system in accordance with any of thepreceding system embodiments, wherein the system further comprises asample pick up means fluidly connected to the metering device.

S4. The liquid chromatography system in accordance with the precedingembodiment, wherein the sample pick up means is a needle.

S5. The liquid chromatography system in accordance with any of thepreceding two embodiments, wherein the system further comprises a seatfor receiving the sample pick up means.

S6. The liquid chromatography system in accordance with any of thepreceding system embodiments, wherein the system further comprises aseparation column and an analytical pump adapted to push the sampletowards and through the separation column.

S7. The liquid chromatography system in accordance with any of thepreceding system embodiments, wherein the system further comprises awaste.

S8. The liquid chromatography system in accordance with any of thepreceding system embodiments, wherein the system further comprises afirst solvent reservoir.

S9. The liquid chromatography system in accordance with the precedingembodiment, wherein the system further comprises a second solventreservoir.

S10. The liquid chromatography system in accordance with any of thepreceding system embodiments with the features of embodiments S5, S6, S7and S8, wherein the system further comprises a first distributor valveand a second distributor valve, wherein each distributor valve comprisesa plurality of ports and a plurality of connecting elements forchangeably connecting the ports of the respective distributor valve,wherein as regards the first distributor valve, one port is directlyfluidly connected to the seat, two ports are directly fluidly connectedto the trap column, one port is directly fluidly connected to theseparation column, one port is directly fluidly connected to theanalytical pump and one port is directly fluidly connected to the seconddistributor valve; and as regards the second distributor valve, one portis directly fluidly connected to the first distributor valve, one portis directly fluidly connected to the waste, one port is directly fluidlyconnected to a first solvent reservoir and one port is directly fluidlyconnected to the metering device.

S11. The liquid chromatography system in accordance with the precedingembodiment and with the features of embodiment S9, wherein another portof the second distributor valve is directly fluidly connected to thesecond solvent reservoir.

S12. The liquid chromatography system in accordance with any of thepreceding system embodiments, wherein the system is adapted for highpressure liquid chromatography, and preferably for pressures exceeding1000 bar.

S13. The liquid chromatography system in accordance with any of thepreceding system embodiments, wherein the metering device comprises afirst port and a second port to fluidly connect to other components.

S14. The liquid chromatography system in accordance with the precedingembodiment and the features of embodiment S10, wherein the meteringdevice is fluidly connected to the first distributor valve by means ofthe second port and fluidly connected to the second distributor valve bymeans of the first port.

S15. The liquid chromatography system in accordance with any of thepreceding system embodiments, wherein the system does not comprise anypump other than the metering device to introduce the sample into thetrap column.

S16. The liquid chromatography system in accordance with any of thepreceding system embodiments, wherein the system is adapted to carry outthe method recited in any of the preceding method embodiments.

S17. The liquid chromatography system in accordance with any of thepreceding system embodiments, wherein the metering device comprises ahousing and a piston.

Below, use embodiments will be discussed. These embodiments areabbreviated by the letter “U” followed by a number. When reference isherein made to a use embodiment, those embodiments are meant.

U1. Use of the liquid chromatography system in accordance with any ofthe preceding system embodiments for liquid chromatography, inparticular of high pressure liquid chromatography.

U2. Use in accordance with the preceding embodiment to carry out themethod as recited in any of the preceding method embodiments.

U3. Use in accordance with any of the preceding use embodiments, whereinthe metering device is used to push the sample into the trap column.

U4. Use in accordance with any of the preceding use embodiments, whereinthe metering device is used to suck in the sample.

U5. Use in accordance with any of the preceding use embodiments, whereinthe metering device is used to pressurize the trap column before thetrap column is fluidly connected to the separation column.

U6. Use in accordance with any of the preceding use embodiments, whereinthe metering device is used to depressurize the trap column from anelevated pressure to a reduced pressure.

U7. Use in accordance with any of the preceding use embodiments, whereinthe metering device is used to cause a fluid flow from the trap columnto a waste.

U8. Use in accordance with any of the preceding use embodiments, whereinthe metering device is used to suck in solvent.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described with reference to theaccompanying drawings which illustrate embodiments of the invention,without limiting the scope of the invention.

FIG. 1 depicts a liquid chromatography system of a first embodimentaccording to the present invention in a first configuration;

FIG. 2 depicts components of a distributor valve employed in embodimentsof the present invention;

FIG. 3 depicts the system of FIG. 1 in a second configuration (which maybe referred to as the “idle state”);

FIG. 4 depicts the system of FIG. 1 in a third configuration (which maybe referred to as the “sample pick up state”);

FIG. 5 depicts the system of FIG. 1 in a fourth configuration (which maybe referred to as the “trapping state”);

FIG. 6 depicts the system of FIG. 1 in a fifth configuration (which maybe referred to as the “pre-pressurize state”);

FIG. 7a depicts the system of FIG. 1 in a sixth configuration (which maybe referred to as the “backward flush injection state”);

FIG. 7b depicts the system of FIG. 1 in a seventh configuration (whichmay be referred to as the “forward flush injection state”);

FIG. 8 depicts the system of FIG. 1 in an eighth configuration (whichmay be referred to as the “de-pressurize state”); and

FIG. 9 depicts the system of FIG. 1 in a ninth configuration (which maybe referred to as the “washing state”).

It is noted that not all of the drawings carry all the reference signs.Instead, in some of the drawings, some of the reference signs have beenomitted for sake of brevity and simplicity of illustration.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG. 1 schematically depicts a liquid chromatography (“LC”) system 1000in accordance with an embodiment of the present technology. Inparticular, the liquid chromatography system 1000 can be a high pressureliquid chromatography system 1000 (also referred to as a highperformance liquid chromatography system 1000 or abbreviated HPLCsystem), that is a system adapted to be employed with pressuresexceeding 100 bar, preferably exceeding 1.000 bar, such as 1.500 bar. Toperform a LC, in essence, a sample contained in a sample container orsample reservoir 2 has to be transferred into a separation column 4.Different constituents of the sample adhere differently to theseparation column 4. Thus, when an analytical pump 12 causes the sampleto flow through the separation column 4, the different constituents ofthe sample will leave the separation column 4 at different times,allowing the constituents to be subsequently detected.

In some embodiments, the present technology is directed to introducingthe sample into the separation column 4. In essence, this is achieved bya sample pick up means 8 (such as a needle 8) of the LC system 1000being inserted into the sample reservoir 2 (see FIG. 4) and a suctionbeing supplied to a tubing 510 connecting the needle 8 and a meteringdevice 100. Such suction can be supplied to said tubing 510 by a piston106 of the metering device 100 retracting out of a housing 108 of themetering device 100 (that is, the metering device 100 may be used tosuck in the sample). Thus, a sample can be sucked from the samplereservoir 2 into the needle 8. In some embodiments, the sample may alsobe sucked into a tubing end section 512, which tubing end section 512 isadjacent to the needle 8. The tubing end section 512 may also bereferred to as the sample loop 512. The needle 8 can subsequently beseated into a seat 10 which will also be referred to as a needle seat 10(see FIG. 5), and the sample can be pushed onto a trap column 6. Pushingthe sample onto the trap column 6 can be performed by the meteringdevice 100, more particularly by the piston 106 of the metering device100 being moved forward. By switching a distributor valve 200 into anappropriate position (see the alternatives of FIGS. 7a and 7b ), thetrap column 6 can be fluidly connected to the separation column 4. Insuch a state, the analytical pump 12 can cause the sample to flow fromthe trap column 6 to the separation column 12.

In one embodiment, the present technology is directed to using themetering device 100 for multiple tasks and/or steps. In prior artsystems, a metering device was typically used to measure and suck in thesample. These tasks are also performed by the metering device 100 of thepresent technology. However, the metering device 100 of the presenttechnology may also be used for additional and more versatile tasks.Thus, additional components (which have until now been necessary) may beomitted, thereby reducing the complexity of the system and saving space.

As laid out above, the metering device 100 may, for example, also beused to push the sample from the tubing end section 512 to the trapcolumn 6 (also see configuration in FIG. 5)—thus, an additional pumpwhich has until now been necessary to push the sample into the trapcolumn 6 may be omitted. Alternatively or additionally, the meteringdevice 100 may be used to precompress (that is, to pressurize) thesample that is present in the trap column 6 (see the configurationdepicted in FIG. 6) and/or to correspondingly decompress (i.e.,depressurize) the trap column 6 before it is fluidly connected to waste18, which typically is at atmospheric pressure—see FIG. 8 fordecompression and FIG. 9 for fluid connection between trap column 6 andwaste 18.

Any of these tasks may be performed by the metering device 100, therebyreducing the complexity of the system 1000. The reduced complexity maylead to increased fail safety. Furthermore, the corresponding system maybe simpler to service (as there are less components to service).

In the above, the general setup of one embodiment of the presenttechnology has been described. In some embodiments, the described trapcolumn 6 may be of some relevance for the present technology. The trapcolumn 6 is used to preconcentrate the sample: Instead of injecting thesample directly into the separation column, the sample is first guidedto the trap column 6, where the constituents to be analyzed may adhere.These constituents may then be separated for further assessment by anappropriate fluid being pumped through the trap column 6 by means of theanalytical pump 12. It will be understood that when introducing thesample from the trap column 6 into the separation column 4, the sampleand the section of the system 1000 being fluidly connected to theseparation column 4 will be at analytical pressure, i.e. at the pressureat which the separation is performed. As discussed, this may be apressure of several hundred bar, or even a pressure exceeding 1.000 bar.It will be understood that after the sample has been introduced into thetrap column 6 (see FIG. 5), the trap column 6 is typically not yet atthe analytical pressure. Instead, in this state (see FIG. 5), thesection of the system 1000 being fluidly connected to the trap column 6comprises the following: metering device 100, tubing 510 connecting themetering device 100 to the needle 8, needle 8, trap column 6, tubing 520connecting distributor valves 200 and 400 and waste 18. In this sectionand in this state or configuration, there may be atmospheric or ambientpressure, i.e. a pressure sufficiently below the analytical pressure.

In principle, after the sample has been transferred into the trap column6 (see FIG. 5), one could immediately switch the system 1000 to one ofthe states depicted in FIGS. 7a and 7b , that is to a state where thesample is transferred from the trap column 6 to the separation column 4.Thus, the pump 12 would have to bring the trap column 6 and theseparation column 4 to the analytical pressure.

However, in the depicted embodiment of the present technology, the trapcolumn 6 may also be pressurized before it is fluidly connected to theseparation column 4. This is depicted in FIG. 6. Here, the section ofthe system 1000 being fluidly connected to the trap column 6 comprisesthe following: metering device 100, tubing 510 connecting the meteringdevice 100 to the needle 8, needle 8, trap column 6, tubing 520connecting distributor valves 200 and 400. However, in contrast to theconfiguration depicted in FIG. 5, the tubing 520 is not connected to thewaste 18. Instead, the distributor valve 400 is set such that tubing 520includes a “dead end”. In this state, the piston 106 of the meteringdevice 100 may be moved forward to pressurize the section of the system1000 being fluidly connected to the trap column 6 and hence also thetrap column 6. Thus, this section may be brought to an elevated pressureand particularly to the analytical pressure before the trap column 6 isfluidly connected to the separation column 4. This may be advantageousfor various reasons: The trap column 6 may be brought to an elevatedpressure (e.g., to the analytical pressure) in a controlled manner,thereby preventing pressure spikes at the trap column 6 that could occurotherwise and that could damage the trap column. Further, the separationcolumn 4 can be maintained at elevated pressures (e.g., at theanalytical pressure). That is, instead of having to pressurize both thetrap column 6 and the separation column 4 after these two columns havebeen fluidly connected to one another, the trap column 6 is connected tothe separation column 4 when both of them are pressurized. This alsoprevents the separation column 4 from being subjected to pressurealterations and pressure spikes. This may reduce the wear on thecomponents and increase the lifetime of the components and the overallsystem. Further, not having pressure spikes also reduced the likelihoodof the sample being mixed with solvent, i.e., dispersion. Having a lessdispersed sample leads to a more defined peak in subsequent analysis,thereby resulting in an improved analysis.

The embodiment of the present technology depicted in the Figures willnow be described in greater detail. FIG. 1 depicts the liquidchromatography system 1000. The system comprises a sample reservoir 2including a sample to be analyzed, a trap column 6, a separation column4, an analytical pump 12, a metering device 100, a sample pick up means8 (which is here realized as a needle 8), a seat 10 (which is hererealized as a needle seat 10), solvent reservoirs 14, 16, a waste 18,tubing interconnecting different elements of the system 1000, as well astwo distributor valves 200, 400. In some embodiments, the tubing may berealized as capillaries. The distributor valves 200, 400 can be set todifferent states to switch the connection between different elements.One exemplary realization of a distributor valve 200 is depicted in FIG.2. Each distributor valve 200 may comprise a stator 210 and a rotor 220.The stator 210 may comprise ports 212 to which different elements may beconnected (e.g., in the embodiment depicted in FIG. 1, each of theneedle seat 10, the analytical pump 12, the separation column 4 and thetubing 520 to the other distribution valve 400 is fluidly connected toone port of the distributor valve 200, respectively, and the trap column6 is fluidly connected to two ports of this distributor valve 200). Therotor 220 may comprise connecting elements 222, such as grooves 222,that may interconnect different ports 212 of the stator element 210. Forexample, FIG. 1 depicts a configuration where each connecting element222 of the rotor of the left distribution valve 200 interconnects twoports of said distribution valve, respectively, while the stator and therotor of the second distribution valve 400 are in such a configurationthat none of the ports in the second distribution valve are connected toone another. It will be understood that whenever two elements aredescribed to be connected to one another, this denotes a fluidconnection, i.e., a connection where a fluid may flow from one elementto the other, unless otherwise specified or unless clear to the skilledperson that something different is meant. Furthermore, also the term“directly fluidly connected” will be used herein. A direct fluidconnection denotes a fluid connection between a port of a valve andanother element, when there is no further valve port present in thisconnection, i.e. in the way between said port of a valve and the otherelement. For example, in the configuration depicted in FIG. 1,analytical pump 12 is directly fluidly connected to the central port ofthe left valve 200. This analytical pump 12 is fluidly connected to theseparation column 4, however, the fluid connection between theanalytical pump 12 and the separation column 4 is not a direct one, asthere are two valve ports in the fluid way between the analytical pump12 and the separation column 4. FIG. 1 also depicts blind plugs 230,430. In the embodiments depicted in FIG. 1, valve 200 comprises onebling plug 230 and valve 400 comprises two blind plugs 430. Blind plugs230, 430 may be used to close off ports in the distributor valves 200,400. Thus, the distributor valves 200, 400 may be identical to oneanother (and one differ by the use of the blind plugs 230, 430), whichmay simplify the productions process. More particularly, in theembodiment depicted in FIG. 1, each distribution valve 200, 400comprises 7 ports, however, two ports of the right distribution valve400 and one port of the left distribution valve 200 are closed off bythe discussed bling plugs 230, 430. The system 1000 may also comprise apressure sensor 20. The pressure sensor 20 may be fluidly connected tothe metering device 100 (e.g., it may be disposed between meteringdevice 100 and the second switching valve 400).

In FIG. 1, the system or setup 1000 is in an idle position: flow of theanalytical pump 12 is passed through the first valve 200 directly to theseparation column 4. The needle 8 is in the needle seat 10. The rightvalve 400, which valve 400 is responsible for the selection of trapfluids and for providing the Compress position, is set here to“Compress”. That is, the valve 400 is set such that the tubing section520 connecting the first valve 200 to the second valve 400 includes a“dead end”.

FIG. 3 depicts how the metering device 100 may get filled with a firstportion of trap solvent. The metering device 100 has two connectionports 102, 104, which are also referred to as first connection port 104and second connection port 102. The right valve 400 connects port 102 ofthe metering device 100 (which port 102 may also be referred to as aninput) with a solvent reservoir 14. The other side, i.e., the otherconnection port 104 of the metering device 100 is closed over the tubing510 connecting the metering device 100 and the needle 8, which tubing510 may include a buffer loop 514, the needle seat 10, the trap column6, the first valve 200, tubing 520 and the second valve 400. The bufferloop 514 may provide an additional length of tubing to allow movement ofthe needle 8. In the depicted position, the piston 106 of the meteringdevice 100 can pull back while raising solvent from solvent reservoir14. It is noted that valve 400 may also be switched to such a positionthat, instead, solvent may be supplied from solvent reservoir 16 to themetering device 100. That is, in simple words, FIG. 3 depicts aconfiguration where trap solvent may be supplied to the metering device100 from solvent reservoir 14. Furthermore, there may also be a fluidflow from the analytical pump 12 through the separation column in thisconfiguration. That is, in the configuration of FIG. 3, the meteringdevice 100 may fill itself with a solvent.

FIG. 4 depicts a configuration where the right valve 400 again entersthe compress position, i.e., the state where the metering device 100 isclosed at port 104, i.e. where this port 104 is connected to a dead end.More particularly, in the configuration depicted in FIG. 4, the tubing520 interconnecting the valves 200 and 400 includes a dead end. Themetering device 100 is first closed at both ports 102, 104, or, in otherwords, in the front and in the back—that is, both ports 102, 104 areconnected to “dead ends”, though it is noted that the connection of port102 to a dead end is optional. The needle 2 may be moved to the samplereservoir 2 and the port 102 of the metering device 100, which port 102connects the metering device to the tubing 510, may be opened—i.e. thetubing 510 does no longer lead to a dead end, but to sample reservoir 2.That is, the metering device 100 may be opened via the buffer loop. Asthe piston 106 of the metering device 100 moves back, the sample isdrawn up into the needle 8 and optionally also into the tubing section512 adjacent to the needle 8. That is, the metering device 100 may suckin the sample.

FIG. 5 depicts how after the sample is drawn, the needle 8 returns tothe needle seat 10. The right valve 400 connects a side of the trapcolumn 6 facing away from the sample with the waste 18. In thisposition, the piston 106 of the metering device 100 can move forward andtherefore push the sample with the previously raised trap solvent to thetrap column 6. Components which do not adhere to the trap column 6 getpushed out to waste 18. That is, the metering device is used to push thesample into the trap column 6, which may also be referred to as“loading” of the trap column 6. This process may be repeated if theright valve 400 again connects the port 104 (which may also be referredto as the rear output) of the metering device 100 with the solventreservoirs 14 or 16 and therefore allows the metering device 100 toraise fresh trap solvent. That is, more trap solvent may be introducedinto the section of the system fluidly connected to the trap column 6 inFIG. 5. To do so, valve 400 is moved to connect tubing 530 to solventreservoir 14 or 16 (that is the configuration of valve 400 in FIG. 3),thereby “opening” port 104, which is no longer connected to a dead end,and port 102 of metering device 100 is “closed” (i.e., it is connectedto a dead end). When the piston 106 is moved back in such aconfiguration, solvent is drawn from the solvent reservoir 14 (or 16)into the metering device 100. Subsequently, port 104 can be closed(i.e., connected to a dead end) and port 102 be opened (i.e., notconnected to a dead end). Then, piston 106 may be moved forward tosupply the solvent into tubing section 510 to thereby supply moresolvent (and potentially also more sample if there are any residues inthe tubing) towards the trap column 6. This process may also be referredto as trapping (and retrapping) the sample.

FIG. 6 depicts the configuration where the sample that has been trappedon the trap column 6 and the components that are fluidly connected tothe trap column 6 are pressurized (or “precompressed”). The right valve400 switches back to the compress position, i.e., to the position wheretubing 520 has a dead end. In the depicted configuration, the trapcolumn 6 is fluidly connected to two dead ends, i.e., it is notconnected to the ambient atmosphere. In other words, it is isolated fromthe ambient atmosphere. The piston 106 in the metering device 100 movesforward, such that volume in the tubing 510 (which includes the bufferloop 514), the trap column 6, the metering device 106 and theconnections is compressed. It can be compressed until analyticalpressure is reached. By this step, the sample in the trap column 6 maybe brought to an elevated pressure, such as to the analytical pressure.That is, the metering device 100 may compress or pressurize the trapcolumn 6. By means of the pressure sensor 20, one may monitor thepressure in the section fluidly connected to the pressure sensor 20. Inthe configuration depicted in FIG. 6, this section also comprises thetrap column 6. Thus, one may bring the pressure in this section to theanalytical pressure. The sensor 20 may also be used for monitoring thedecompression of a section of the system. That is, by means of thepressure sensor 20, one may monitor the pressure in this section andadapt the pressure change in this section accordingly.

The trap column 6 may now be fluidly connected to the analytical pump 12on one side and to the separation column 4 on the other side. This maybe done in different ways, depicted in FIGS. 7a and 7b , respectively.

FIG. 7a depicts a configuration, which may be referred to as the “injectbackflush” configuration. The left valve 200 is switched such that thetrap column 6 is introduced into the analytical flow in such a way thatthe analytical flow pushes the sample back out the side it came from(backward flush). That is, the flow direction through the trap column 6is opposite to the flow direction with which the trap column 6 wassupplied with the sample. Put differently, a first end of the trapcolumn 6 that has been upstream to a second end of the trap column 6when being provided with the sample is now downstream to this second endwhen the analytical flow is provided through the trap column 6.

Alternatively, as depicted in FIG. 7b , the analytical flow can push thesample further in the direction of the trap flow (forward flush). Thatis, the flow direction through the trap column 6 is parallel to the flowdirection with which the trap column 6 was supplied with the sample. Putdifferently, a first end of the trap column 6 that has been upstream toa second end of the trap column 6 when being provided with the sample isnow also upstream to this second end when the analytical flow isprovided through the trap column 6.

FIG. 8 depicts a configuration similar to the configuration depicted inFIG. 6. Again, the trap column 6 is fluidly connected to the tubing 520connecting valves 200 and 400 and to the tubing 510 (including thebuffer loop 514) providing a connection to the metering device 100. Bymoving the piston 106 back, the pressure still present in the portion ofthe system 1000 fluidly connected to the trap column 6 (including thebuffer loop 514, the metering device 100 and the connections) can bereduced. That is, this configuration may also be referred to as thedecompress state. Again, it may be the metering device 100 providing forthis decompression. The decompression may be monitored by means of thepressure sensor 20. The controlled decompression may be advantageous fordifferent reasons. By means of the controlled decompression, nouncontrolled and more rapid decompression occurs. Thus, the controlleddecompression leads to less abrasion on the valve 200 and othercomponents and also prevents fluid from rapidly exiting the system(which could be a risk for a user). Furthermore, the controlleddecompression also lowers the risk of components outgassing in the fluidin the system.

FIG. 9 depicts a configuration where the trap column 6 is fluidlyconnected to the waste 18. In this state, if any residual pressureremains in the trap column 6 and the components fluidly connectedthereto, it can be dissipated. That is, in comparison to FIG. 8, theright valve 400 can be switched to waste 18. This state may also bereferred to as the equilibrium phase. The right valve 200 can reconnectthe metering device 100 with solvent reservoir 14 or 16 from thisposition, draw up the respective solvent, and thus wash the trap column6 and components fluidly connected thereto (including the buffer loop514, the needle seat 10 and the trap column 6). That is, the meteringdevice 100 may also be used to wash the system 1000. The washing istypically done iteratively with the configurations depicted in FIGS. 3and 9. That is, the left valve 200 remains in one position and the rightvalve is iteratively switched. In the state depicted in FIG. 3, solventmay be drawn into the metering device and in the state depicted in FIG.9, the components fluidly connected to the metering device 100 (alsoincluding the trap column 6) may be washed. Furthermore, it will beunderstood that washing and equilibrating may be performedsimultaneously. Equilibrating may be done by means of the first (left)valve 200 by having the analytical pump 12 fluidly connected with theseparation column 4 (i.e., valve 200 may not be switched whenequilibrating) and the second (right) valve 400 being iterativelyswitched, as discussed.

Whenever a relative term, such as “about”, “substantially” or“approximately” is used in this specification, such a term should alsobe construed to also include the exact term. That is, e.g.,“substantially straight” should be construed to also include “(exactly)straight”.

Whenever steps were recited in the above or also in the appended claims,it should be noted that the order in which the steps are recited in thistext may be accidental. That is, unless otherwise specified or unlessclear to the skilled person, the order in which steps are recited may beaccidental. That is, when the present document states, e.g., that amethod comprises steps (A) and (B), this does not necessarily mean thatstep (A) precedes step (B), but it is also possible that step (A) isperformed (at least partly) simultaneously with step (B) or that step(B) precedes step (A). Furthermore, when a step (X) is said to precedeanother step (Z), this does not imply that there is no step betweensteps (X) and (Z). That is, step (X) preceding step (Z) encompasses thesituation that step (X) is performed directly before step (Z), but alsothe situation that (X) is performed before one or more steps (Y1), . . ., followed by step (Z). Corresponding considerations apply when termslike “after” or “before” are used.

While in the above, a preferred embodiment has been described withreference to the accompanying drawings, the skilled person willunderstand that this embodiment was provided for illustrative purposeonly and should by no means be construed to limit the scope of thepresent invention, which is defined by the claims.

What is claimed is:
 1. A method performed in a liquid chromatographysystem, the method comprising a metering device providing a loading flowof solvent to transfer a sample into a trap column, wherein the methodfurther comprises the metering device sucking in solvent and sample fromdifferent reservoirs, wherein the sample flow precedes the solvent flow.2. The method according to claim 1, wherein the liquid chromatographysystem comprises a separation column, and wherein the method furthercomprises: pressurizing the trap column to a first pressure while thetrap column is isolated from an ambient atmosphere; fluidly connectingthe separation column to the trap column; and pushing the sample fromthe trap column to the separation column, wherein the step ofpressurizing the trap column to the first pressure is performed beforethe trap column is fluidly connected to the separation column.
 3. Themethod according to claim 2, wherein the metering device pressurizes thetrap column to the first pressure.
 4. The method according to claim 2,wherein the liquid chromatography system comprises: A) an analyticalpump; B) the waste reservoir; C) a needle; D) a seat; E) a firstdistributor valve comprising: a) a plurality of ports; and b) aplurality of connecting elements configured to changeably connect to theplurality of ports of the first distributor valve, wherein the pluralityof ports of the first distributor valve comprises: i) a first portdirectly fluidly connected to the seat; ii) a second port and a thirdport that are both directly fluidly connected to the trap column; iii) afourth port directly fluidly connected to the separation column; iv) afifth port directly fluidly connected to the analytical pump; and v) asixth port directly fluidly connected to a second distributor valve; F)the second distributor valve comprising: a) a plurality of ports and b)a plurality of connecting elements configured to changeably connect theports of the second distributor valve, wherein the plurality of ports ofthe second distribution valve comprises: i) a seventh port directlyfluidly connected to the first distributor valve; ii) an eighth portdirectly fluidly connected to the waste reservoir; iii) a ninth portdirectly fluidly connected to the first solvent reservoir; and iv) atenth port directly fluidly connected to the metering device; andwherein the method further comprises: fluidly connecting the trap columnto the analytical pump; pushing the sample from the trap column to theseparation column with the analytical pump; and fluidly connecting thetrap column to the waste reservoir and flowing a fluid from the trapcolumn to the waste reservoir.
 5. The method according to claim 1wherein the waste reservoir is at ambient pressure.